Epicardial fat thickness and oxidative stress parameters in patients with subclinical hypothyroidism

Impact of Epicardial Adipose Tissue on Right Cardiac Function and Prognosis in Pulmonary Arterial Hypertension

BACKGROUND

Although epicardial adipose tissue (EAT) is linked to effects on survival in left-sided heart failure, the association between EAT and right-sided heart failure caused by pulmonary arterial hypertension (PAH) remains unknown.

RESEARCH QUESTION

What are the potential impacts of EAT volume (EATV) on right ventricular function, biomarkers of myocardial injury, and long-term prognosis in patients with PAH?

STUDY DESIGN AND METHODS

A total of 135 age- and BMI-matched patients with PAH and 49 control participants were included in this study. EATV was quantified by using cardiac magnetic resonance and was related to clinical correlates, N-terminal pro-brain natriuretic peptide, and cardiac function. Levels of EATV associated with the risk of clinical worsening were evaluated on a continuous scale (restricted cubic splines) and by previously defined centile categories with Cox proportional hazards regression models and Kaplan-Meier survival estimates.

RESULTS

Compared with the control participants, patients with PAH had a lower EATV (ln [EATV], 3.2 ± 0.8 mL vs 3.5 ± 0.7 mL; P = .034). The association of EATV with right ventricular end-diastolic volume (Pnonlinear = .001), right ventricular end-diastolic volume index (P < .001), right ventricular cardiac output (P = .003), N-terminal pro-brain natriuretic peptide (P = .030), and the risk of clinical worsening (P = .014) was U shaped. Compared with individuals with middle-level EATV, multivariable-adjusted hazard ratio for clinical worsening was 6.0 (95% CI, 1.3-27.8) for the individuals with low-level EATV and 6.8 (95% CI, 1.5-30.2) for high-level EATV in patients with PAH.

INTERPRETATION

Patients with PAH had a decreased EATV compared with control participants. EATV exhibited a U-shaped association with right ventricular function and biomarkers of myocardial injury in patients with PAH. Low and high levels of EATV might reduce long-term event-free survival in patients with PAH.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry; No. ChiCTR2100049804; www.chictr.org.cn.

Relationship of subclinical hypothyroidism on epicardial adipose tissue: a systematic review and meta-analysis

Accumulation of epicardial adipose tissue (EAT) and Subclinical hypothyroidism (SH) are associated with increased cardio-metabolic risk. The objective of this study was to quantitatively compare EAT thickening between patients with SH and healthy controls. Therefore, after searching the PubMed/MEDLINE, Embase, Science Direct, Scopus, Google Scholar, and Cochrane databases; we analyzed a group of observational studies who compare the EAT changes between SH vs control groups. A total of 9 studies were included in the final analysis, for a total of 424 patients with SH and 330 controls. Random or fixed effects models were used. Pooled analysis revealed that HS increased EAT (MD: 1.0 mm [0.40; 1.50]; P < 0.01). This meta-analysis suggests that the amount of EAT is significantly increased in SH patients. EAT might be a marker of cardiovascular risk in patients with SH.

SERUM LEVELS OF OXIDATIVE STRESS MARKERS IN SUBCLINICAL AND OVERT HYPOTHYROIDISM VERSUS CONTROL GROUP IN POPULATION OF KUTAHYA CITY, TURKEY

Background: Overproduction of oxygen-related free radicals and inadequate antioxidant defense are critical in hypothyroidism, as they might lead to future life-threatening diseases. The objectives of this study were to compare serum levels of oxidative stress markers; total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), paraoxonase-1 (PON-1), and arylesterase (ARYL) in patients with subclinical hypothyroidism (SH) and overt hypothyroidism (OH) versus healthy controls in population of Kutahya city, Turkey.Materials Methods: This cross-sectional study was conducted at Department of Biochemistry, Faculty of Medicine, Kutahya University of Health Sciences, Kutahya, Turkey, from July to December, 2016. Three study groups of 45 each were formed as healthy controls, patients with SH and OH. Serum levels of TOS, TAS, OSI, PON-1, and ARYL were five research variables with ratio scale, but skewed, so described by median and IQR with 95% Cl. Kruskal-Wallis and multiple comparison tests were used for hypotheses testing.Results: Serum levels of TOS and OSI were higher in SH group (p-values 0.032; .0001; respectively) and OH group (p-values .0001; .0001, respectively) than healthy controls, while serum levels of TAS, PON-1 and ARYL were lower in SH group (p-values .0001; .0001; .0001, respectively) and OH group (p-values .0001; .0001; .0001, respectively) than control group.Conclusion: Our study showed that serum levels of TOS and OSI were higher in subclinical and overt hypothyroidism than in healthy controls; while serum levels of TAS, PON-1, and ARYL were lower in subclinical and overt hypothyroidism than in healthy controls.

Prevalence and Clinical Significance of Subclinical Hypothyroidism in Diabetic Peripheral Neuropathy

Background and Aim

Diabetic peripheral neuropathy (DPN) is one of the most common and disabling complications of DM. Many studies documented the prevalence of clinical and subclinical hypothyroidism (SCH) in diabetic patients but not in the particular group of patients with DPN. The present study aimed to determine the prevalence of SCH in DPN patients and to evaluate its association with severity of DPN.

Patients and Methods

The present cross-sectional study was conducted on 300 consecutive patients with DPN. The clinical manifestations of DPN were documented according to the validated Arabic version of the Michigan Neuropathy Screening Instrument. Severity of DPN was categorized into mild (6–8 points), moderate (9–11 points) or severe (12+ points) according to the Toronto Clinical Scoring System. All patients were submitted to careful history-taking and full clinical and neurological examination. Patients were diagnosed with SCH if they had TSH level above the upper limit of the normal reference range in association with normal free thyroxine (FT4) level.

Results

SCH was prevalent in 53 patients (17.7%, 95% CI: 13.5%–22.5%). Patients with SCH had significantly higher frequency of severe DPN (52.8% versus 28.3%, p=0.003). It was also shown that patients with SCH had significantly higher HbA1c (8.4 ± 1.0 versus 7.3 ± 1.2%, p<0.001) and HOMA-IR (3.7 ± 0.8 versus 2.7 ± 0.9, p<0.001) when compared with patients without SCH. Logistic regression analysis identified patients’ age [OR (95% CI): 1.06 (1.03–1.08), p<0.001], HbA1c [OR (95% CI): 2.2 (1.7–2.9), p<0.001] and SCH [OR (95% CI): 7.7 (3.6–15.5), p<0.001] as independent predictors of DPN severity.

Conclusion

The present study showed that SCH is highly prevalent in DPN patients and is independently related to its severity.

Physical Exercise Potentially Targets Epicardial Adipose Tissue to Reduce Cardiovascular Disease Risk in Patients with Metabolic Diseases: Oxidative Stress and Inflammation Emerge as Major Therapeutic Targets

Excess epicardial adiposity, within a state of obesity and metabolic syndrome, is emerging as an important risk factor for the development of cardiovascular diseases (CVDs). Accordingly, increased epicardial fat thickness (EFT) implicates the exacerbation of pathological mechanisms involving oxidative stress and inflammation within the heart, which may accelerate the development of CVDs. This explains increased interest in targeting EFT reduction to attenuate the detrimental effects of oxidative stress and inflammation within the setting of metabolic syndrome. Here, we critically discuss clinical and preclinical evidence on the impact of physical exercise on EFT in correlation with reduced CVD risk within a setting of metabolic disease. This review also brings a unique perspective on the implications of oxidative stress and inflammation as major pathological consequences that link increased EFT to accelerated CVD risk in conditions of metabolic disease.

Meta-analytic evidence for increased low-grade systemic inflammation and oxidative stress in hypothyroid patients. Can levothyroxine replacement therapy mitigate the burden?

PURPOSE

This series of meta-analyses were aimed to elucidate the impact of hypothyroidism on low-grade systemic inflammation and oxidative stress assessed by C-reactive protein (CRP) and malondialdehyde (MDA) respectively; and to evaluate the effect of levothyroxine replacement therapy (LRT) on those outcomes.

METHODS

PubMed database and the key studies references were searched prior to March 3, 2020. Data on serum or plasma CRP and MDA levels in SHT (subclinical) and/or OHT (overt) hypothyroid patients and controls were extracted to compute overall standardized mean differences (SMD) by the random-effects model.

RESULTS

A total of 93 studies were entered into analyses and ten main meta-analyses were performed. OHT (SMD = 0.72 [0.39; 1.04], k = 35), SHT (SMD = 1.58 [0.78; 2.38], k = 56) and even mild SHT (TSH < 10 mU/L, SMD = 2.19 [0.02; 4.37], k = 13) proved to have a detrimental effect on CRP levels. LRT showed a favorable effect on CRP levels, particularly in OHT (SMD = -0.30 [-0.57; -0.02], k = 17). Increased levels of MDA were also found, especially in OHT (SMD = 2.49 [0.66; 4.31], k = 13). LRT may also improve MDA levels; however future studies would further validate the advantageous effect of LRT in hypothyroidism. Heterogeneity primarily originated from different study designs and geographic locations.

CONCLUSION

Overall, these meta-analyses reveal that screening for hs-CRP and MDA in hypothyroid patients as simple biomarkers of low-grade systemic inflammation and oxidative stress may become a useful tool to identify those at increased risk who may benefit most from early interventions.

Subclinical Hypothyroidism as an Independent Determinant of Left Atrial Dysfunction in the General Population

PURPOSE

Although subclinical hypothyroidism (SCH) is a common clinical entity and carries independent risk for incident heart failure (HF), its possible association with subclinical cardiac dysfunction is unclear. Left ventricular global longitudinal strain (LVGLS) and left atrial (LA) phasic strain can unmask subclinical left heart abnormalities and are excellent predictors for HF. This study aimed to investigate the association between the presence of SCH and subclinical left heart dysfunction in a sample of the general population without overt cardiac disease.

METHODS

We examined 1078 participants who voluntarily underwent extensive cardiovascular health check-ups, including laboratory tests and 2-dimensional speckle-tracking echocardiography to assess LVGLS and LA reservoir, conduit, and pump strain. SCH was defined as an elevated serum thyroid-stimulating hormone level with normal concentration of free thyroxine.

RESULTS

Mean age was 62 ± 12 years, and 56% were men. Seventy-eight (7.2%) participants exhibited SCH. Individuals with SCH had significantly reduced LA reservoir (37.1 ± 6.6% vs 39.1 ± 6.6%; P = 0.011) and conduit strain (17.3 ± 6.3% vs 19.3 ± 6.6%; P = 0.012) compared with those with euthyroidism, whereas there was no significant difference in left ventricular ejection fraction, LA volume index, LVGLS, and LA pump strain between the 2 groups. In multivariable analyses, SCH remained associated with impaired LA reservoir strain, independent of age, traditional cardiovascular risk factors, and pertinent laboratory and echocardiographic parameters. including LVGLS (standardized β -0.054; P = 0.032).

CONCLUSIONS

In an unselected community-based cohort, individuals with SCH had significantly impaired LA phasic function. This association may be involved in the higher incidence of HF in subjects with SCH.

Echocardiographic assessment of epicardial fat tissue thickness in patients with severe periodontitis

OBJECTIVES

This study aims to assess the thickness of epicardial fat tissue (EFT), a sign of cardiovascular risk, using echocardiography in patients with severe periodontitis.

METHODS

Thirty-three patients with stage III or IV periodontitis and 33 healthy participants were enrolled into the study. Epicardial fat tissue thickness was measured perpendicularly via echocardiography of the free wall of the right ventricular at end-diastole in three cardiac cycles. Body mass index (BMI) was calculated by dividing weight in kilograms by the height in meters squared. EFT to BMI ratio (EFT/BMI) was measured by dividing EFT by the BMI.

RESULTS

There was no significant difference between study patients and the control group as regards to the frequency of diabetes, hypertension, smoking, and hyperlipidemia. The EFT and EFT/ BMI ratio were significantly different in the control and periodontitis groups (0.51±0.17 vs. 0.77±0.16, respectively; p ≤0.001) (0.021±0.008 vs. 0.030±0.006, respectively; p≤0.001). Pearson's correlation coefficient demonstrated a significant relationship between EFT and the clinical parameters of periodontitis (p<0.001) CONCLUSIONS: EFT thickness measured by echocardiography appears to be associated with severe periodontitis and may thus be an indirect sign of cardiovascular disease in periodontitis patients.

Epicardial Fat Thickness in Children with Subclinical Hypothyroidism and Its Relationship to Subclinical Atherosclerosis: A Pilot Study

BACKGROUND/AIMS

Thyroid hormones (TSH) play a key role in the working of the cardiovascular system, with direct effects on cardiac function, vascular system, and atherosclerotic factors. Epicardial adipose tissue, the visceral fat of the heart, has emerged as a new cardiometabolic risk marker because of its close anatomical proximity to the myocardium and coronary artery. This study aimed to evaluate epicardial fat thickness (EFT) in children with subclinical hypothyroidism (SH) and its relation to early atherosclerotic changes.

METHODS

The study included 32 children with SH due to autoimmune thyroiditis and 32 healthy children matched for age and gender as control group. Patients and controls underwent anthropometric evaluation and measurement of fasting lipids, glucose, insulin, homeostasis model assessment for insulin resistance and high-sensitivity C-reactive protein (hs-CRP). TSH, free thyroxine (FT4 and FT3) and antithyroid autoantibodies (antithyroid peroxidase and thyroglobulin antibodies) were also measured. Conventional echo-cardiography was used to assess EFT. Noninvasive ultrasound was used to measure carotid intima-media thickness and brachial artery flow-mediated dilation (FMD) responses.

RESULTS

Compared to controls, patients had higher atherogenic index (AI) and hs-CRP (p = 0.001 for each). Conventional echocardiography revealed that patients with SH had higher EFT (p = 01) and significantly lower FMD response compared with the control (p = 0.001). In multivariate analysis, EFT values were significantly correlated with TSH (OR 1.2; 95% CI 1.04-1.34; p = 0.01), hs-CRP (OR 1.1; 95% CI 1.09-1.14; p = 0.001, AI (OR 1.6; 95% CI 1.17-2.03; p = 0.001), and FMD response (OR 2.4; 95% CI 1.14-2.53; p = 0.01).

CONCLUSIONS

Our study demonstrated that EFT is higher in children with SH compared with controls and associated with FMD responses. Measurement of EFT by echocardiography in children with SH may help to identify those at high risk of developing subclinical atherosclerosis.

Protective effects of benfotiamine on irisin activity in methotrexate-induced liver injury in rats

INTRODUCTION

Methotrexate (MTX) causes hepatotoxicity by producing oxidative stress. Benfotiamine and irisin have protective effects against oxidative stress. The aim of this study was to investigate the changes in irisin activity in the liver as a result of toxicity produced by MTX and the protective role of benfotiamine in the hepatotoxicity.

MATERIAL AND METHODS

Rats were divided into 4 groups as follows: control, benfotiamine (50 mg/kg, oral gavage (o.g.), for 14 days), MTX (MTX 20 mg/kg intraperitoneally (i.p.) on day 1), MTX + benfotiamine (MTX 20 mg/kg (i.p.) on day 1, then 50 mg/kg (o.g.) benfotiamine for 14 days). Liver tissue was used to examine histopathological and immunohistochemical changes. Serum was used to look for oxidative stress markers (total antioxidant status (TAS) and total oxidant status (TOS)).

RESULTS

Administration of MTX caused a significant TOS increase and TAS decrease in the serum as compared to the control group. Immunohistochemically, irisin was significantly increased in immunoreactivity in the MTX group as compared to the control group (p < 0.05). Significant histopathological improvement and decrease in serum TOS levels were observed in the MTX + benfotiamine group compared to the MTX group (p < 0.05). In addition, an increase in TAS level and a decrease in irisin immunoreactivity were observed but they were not statistically significant (p > 0.05).

CONCLUSIONS

Our results showed that MTX caused an increase in the activity of irisin after producing toxicity in the liver. In addition, we found that benfotiamine was effective in preventing damage caused by MTX in the liver.

Triiodothyronine levels were positively correlated with opening of collateral circulation in cerebral infarction patients with large artery atherosclerosis

INTRODUCTION

Non-thyroidal illness syndrome (NTIS) is one of the signs for poor prognosis of cerebral infarction (CI), but its risk factors had never been explored. In this study, we analyzed the potential effect of collateral circulation on prognosis prediction of triiodothyronine for large artery atherosclerosis cerebral infarction (LAA-CI) patients.

MATERIAL AND METHODS

Clinical data of CI patients between 2012 and 2014 were collected. Imaging inspection was used for determining TOAST classification and evaluating collateral circulation. One-year follow-up was conducted for mRS score by telephone.

RESULTS

T3 level in the NTIS group (p = 0.001) was significantly decreased while TSH level (p < 0.001) was increased. Patients in the NTIS group had a poorer prognosis (p = 0.008) and the main reason was the high mortality (p = 0.002). NTIS predicted poor collateral circulation (p = 0.026) and good collateral circulation tended to be less likely concomitant with NTIS (p = 0.001). Logistic regression analysis showed that triiodothyronine concentrations (OR = 4.760, 95% CI: 1.981-11.456, p < 0.001) were positively correlated with but advanced age (OR = 0.756, 95% CI: 0.645-0.886, p = 0.001) negatively with opening of collateral circulation.

CONCLUSIONS

Poor opening of collateral circulation was likely to mediate the prediction of NTIS for prognosis of LAA-CI patients.

Microenvironment of Immune Cells Within the Visceral Adipose Tissue Sensu Lato vs. Epicardial Adipose Tissue: What Do We Know?

The chronic low-grade inflammation of the visceral adipose tissue is now fully established as one of the main contributors to metabolic disorders such as insulin resistance, subsequently leading to metabolic syndrome and other associated cardiometabolic pathologies. The orchestration of immune response and the "ratio of responsibility" of different immune cell populations have been studied extensively over the last few years within the visceral adipose tissue in general sense (sensu lato). However, it is essential to clearly distinguish different types of visceral fat distribution. Visceral adipose tissue is not only the classical omental or epididymal depot, but includes also specific type of fat in the close vicinity to the myocardium-the epicardial adipose tissue. Disruption of this type of fat during obesity was found to have a unique and direct influence over the cardiovascular disease development. Therefore, epicardial adipose tissue and other types of visceral adipose tissue depots should be studied separately. The purpose of this review is to explore the present knowledge about the morphology and dynamics of individual populations of immune cells within the visceral adipose tissue sensu lato in comparison to the knowledge regarding the epicardial adipose tissue specifically.

Non-invasive markers of cardiovascular risk in patients with subclinical hypothyroidism: A systematic review and meta-analysis of 27 case control studies

It has been reported that subclinical hypothyroidism (SCH) is closely related to subclinical atherosclerosis. According to the impact of SCH on noninvasive markers of cardiovascular risk, we fulfilled a meta-analysis of included studies to provide an integrated overview. We searched electronic databases and included all relevant studies involving SCH and epicardial adipose tissue (EAT), carotid intima-media thickness (CIMT), pulse wave velocity (PWV), flow-mediated dilation (FMD) and glyceryl trinitrate-induced dilation (GNT- induced dilation). The result was calculated in a meta-analysis to assess the impact of SCH on these markers. A total of 27 studies were entered in the final analysis. Compared with euthyroid subjects, SCH patients exhibited a significantly increased CIMT (SMD: 0.369 mm; 95%CI: 0.038, 0.700; P = 0.029) and EAT (SMD: 1.167 mm; 95%CI: 0.869, 1.466; P = 0.000) and increased PWV (SMD: 3.574 m/s; 95%CI: 0.935, 6.213, P = 0.008). We also found significantly lower FMD (SMD: −1.525%, 95%CI: −2.156, −0.894, P = 0.000) and lower GNT-induced dilation (SMD: −0.384%, 95%CI: −0.625, −0.142, P = 0.002). Sensitivity analysis and subgroup analysis confirmed the above results. Our meta-analysis confirmed a significant association of SCH and cardiovascular risk with arterial wall thickening and stiffening and endothelial dysfunction. These findings will help to establish detailed cardiovascular prevention strategies for SCH patients.

The effect of L-thyroxine substitution on oxidative stress in early-stage diabetic nephropathy patients with subclinical hypothyroidism: a randomized double-blind and placebo-controlled study

PURPOSE

To study oxidative stress status of early type 2 diabetic nephropathy (DN) patients with subclinical hypothyroidism (SCH) and to assess effect of L-thyroxine therapy on the oxidative stress in these patients.

METHODS

It is a randomized double-blind and placebo-controlled trial. A total of 48 patients with early type 2 DN were included as Euthyroid group, and 92 early type 2 DN with SCH were selected and randomly assigned to L-thyroxine treatment group (LT4 group) and placebo group (SCH group). Changes in urinary albumin excretion rate (UAER), serum malondialdehyde (MDA), superoxide dismutase (SOD) activity, urine 8-hydroxyl deoxyguanosine (8-OHdG), serum creatinine, estimated glomerular filtration rate, and lipid profile before and after 24 weeks of follow-up were examined and compared.

RESULTS

The levels of UAER, MDA, 8-OHdG were higher, while the SOD activity was lower in DN patients with SCH than in DN patients (p < 0.05 for all). In the LT4 group, the levels of UAER, MDA, 8-OHdG decreased significantly (p < 0.05) to levels no longer different from the Euthyroid group. The SOD activity increased significantly. But in SCH group, the levels of mAlb, MDA, 8-OHdG were greater after 24 weeks of follow-up and greater than patients in the Euthyroid group. SOD activity decreased significantly after 24 weeks in the SCH group (p < 0.05).

CONCLUSION

Oxidative stress is greater in the DN patients with SCH, and SCH may exacerbate kidney injury in early DN patients. The LT4 treatment may decrease the oxidative stress and attenuate renal injury in DN patient with SCH.